This invention relates to an electric connector adapted to high-speed transmission.
For the high-speed transmission, a high-speed transmission connector is used. The high-speed transmission connector comprises a socket connector to be connected to a printed circuit board and a plug connector for connecting a flexible printed circuit board (FPC) or a flexible flat cable (FFC) to the socket connector
For example, Japanese Patent No. 3451393 (JP-B) discloses a socket connector and a plug connector of the type. The plug connector disclosed in the Japanese Patent comprises an insulator, a connector fitting portion formed at one end of the insulator to be fitted to the socket connector in a first direction, and a FPC fitting portion formed at the other end of the insulator to be fitted to a FPC or a FFC in the first direction. The FPC fitting portion has a plurality of contact groups disposed inside the insulator. Each of the contact groups includes a pair of signal contacts or paired signal contacts arranged in parallel in a second direction intersecting the first direction and a ground contact disposed between the paired signal contacts.
The above-mentioned plug connector has the ground contacts but a sufficient grounding function is not assured. In addition, the plug connector is inevitably increased in size.